I would look at
http://s3.invisionfree.com/rcdrift or groovydrift.com . Many of the drifters wire up their own lights for their bodies. I'm sure they would be able to help you. also, Tamiya makes a light kit, but it is a bit on the pricy side.
http://www2.towerhobbies.com/cgi-bin...?&I=LXMGB0&P=7